Faster (and safer) equal implementation

[tmcw]

Hello! Love dnd-kit, it's working great in my application.

I'm dealing with quite a lot of data - benchmarking with 40,000 items in a sortable list. dnd-kit is mostly not a bottleneck, but I have noticed that, since I'm using uuids and quite a lot of items, the isEqual method takes up an appreciable amount of the performance profile, and the size of the strings generated can trigger a GC.

Hence: a non-join based isEqual implementation. I did bench this to make sure that it resolves the performance issues - seems to, about a 15x gain, not counting the reduced memory pressure.

joinEqual/short x 1,613,252 ops/sec ±0.66% (89 runs sampled)
joinEqual/equal x 1,808 ops/sec ±0.65% (90 runs sampled)
joinEqual/notEqual x 1,891 ops/sec ±0.59% (93 runs sampled)
joinEqual/differentLength x 1,879 ops/sec ±0.89% (90 runs sampled)
iterativeEqual/short x 23,996,960 ops/sec ±2.75% (87 runs sampled)
iterativeEqual/equal x 28,280 ops/sec ±2.18% (85 runs sampled)
iterativeEqual/notEqual x 24,164,244 ops/sec ±0.64% (91 runs sampled)
iterativeEqual/differentLength x 24,280,053 ops/sec ±0.52% (90 runs sampled)

Benchmark here

This also fixes a bug in dnd-kit, in which you could have different ID sequences that join to the same thing. For example, if you had: [a, bb, c], and the updated item ids were [ab, b, c] or any other combination of (abbc) then you'd get a false 'equal' through the join-based method.

[changeset-bot]

🦋 Changeset detected

Latest commit: 1aa29e0

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@dnd-kit/sortable	Patch

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[clauderic]

Hey @tmcw, thanks for your contribution! This looks great! Would you mind adding a changeset or giving me write access?

[tmcw]

Yep! Done.

[tmcw]

👋 hey - any chance that this might get released? Still seeing this in my profiles and very excited to remove that bottleneck

[clauderic]

Hey @tmcw, every merged commit gets deployed to npm under the next tag, so you can already upgrade to the packages of @dnd-kit tagged with next:

npm install @dnd-kit/core@next